This question is actually a fallacy because the question itself implies an answer.
This is the fallacy of the Complex Question and it needs to be divided:

1) Is it possible to determine if the Bible is relevant without first assuming it is?

2) If so, how is it relevant?

The answer to the first question is “No,” therefore the second question is not necessary.
You would have to assume the Bible is relevant in order to determine if it is.
This does not mean that the question has no answer. It actually does have a very good answer.

The Bible is relevant because it says it is.

That’s probably not the answer that a skeptic is looking for, but a skeptic is approaching
the problem incorrectly. The Bible doesn't claim to merely be a piece of information to consider.
It claims to be the basis for all information. The basis for all information must be assumed before
information itself can be considered.

It is reasonable to assume that a document that accurately claims to be the basis for all information
is relevant today, but it isn’t reasonable to assume that a document is the basis for all information
just because it says so. Another document that denies the Bible could just as easily say the same thing.

The Bible is special in that it can be proven to be the basis for all information, nevertheless,
that proof isn't possible without the use of information and the Bible is the basis of information.

If you refuse to believe the Bible until it is proven to be relevant, you are actually depending on
the Bible without admitting it. There are at least two things you are assuming when you ask this
question that only the Bible gives you a reason to assume. By asking for proof, you are assuming that the
laws of logic exist. You are assuming that it is possible to weigh concepts logically and arrive at a
conclusion. This idea is based on biblical thinking.

In order for the laws of logic to work, they have to be absolute, invariant, universal and abstract;
like God. They have to have always existed, or else we could not assume that old logic still works.
We would have to expect that they will always work in the future or it wouldn’t make sense to rely on
what we know today. In other words, logic is not natural and must never evolve.
This is assumed to be true when the question is asked. The Bible allows me to make this assumption,
but I’m not the one asking the question.

The other thing that this question depends on is that it is good for us to focus on relevant things
and bad to focus on irrelevant ones. The Bible makes it clear that whatever God thinks is relevant
and because of this, I have a reason to ask questions like this, but why would someone who doesn't
believe in God or in the Bible need to ask?

Both logic and morality are biblical concepts that we are born believing in. We can deny these things
but we can't escape them. The Bible is relevant because it answers our questions.
Until someone shares the contents of the Bible with us, we must live without a reason for the most
fundamental things in life. If we assume the truth of the Bible and argue against the only
available explanation for our assumptions, we only prove that we are in denial.

So, not only is the Bible relevant because it says it is, but you can’t even argue against it
without assuming what it says is true.